geochemie

Geochemistry, sometimes written as Geochemie in German, is the science that studies the chemical composition of the Earth and its rocks, minerals, soils, waters, and atmosphere, and the chemical changes these materials undergo over time. Originating with the work of Victor Goldschmidt in the early 20th century, geochemistry integrates chemistry, geology, physics, and biology to understand Earth's history and its current processes. The field investigates the distribution and abundance of elements in natural environments and the mechanisms that control their transport and transformation.

Geochemistry encompasses several subdisciplines, including isotope geochemistry, which uses stable and radiogenic isotopes to trace sources, ages, and processes; marine and terrestrial geochemistry, which study chemical cycles in oceans, soils, and sediments; organic geochemistry, focusing on hydrocarbons and biomolecules; cosmochemistry, examining the chemical composition of extraterrestrial materials; and environmental geochemistry, addressing pollution, remediation, and human impacts.

Key processes include weathering, dissolution, precipitation, metamorphism, and ore genesis. Geochemical methods rely on analytical techniques such as inductively coupled plasma mass spectrometry (ICP-MS), atomic emission spectroscopy, X-ray fluorescence (XRF), isotope ratio mass spectrometry, and chromatography. Data interpretation uses phase equilibria, geochemical modeling, and mass-balance calculations.

Applications range from mineral exploration and ore deposit modeling to groundwater quality assessment, climate reconstruction through isotopic records, and studies of planetary formation. Geochemistry thus provides a framework to link chemical compositions with geological and environmental processes across spatial and temporal scales.